1. Field of the Invention
The invention relates to a method for effectively predicting the availability of iron (Fe) in foods utilizing ferritin formation in intestinal epithelial cells as an indicator.
2. Description of the Relevant Art
An intestinal epithelial cell line is a useful model for studies of iron uptake in humans. The Caco-2 cell line has been described as such a model in a number of studies (e.g. Glahn et al. 1994. FASEB Journal. vol. 8, no. 5, abstr. No. 4134; Wien et al. 1995. FASEB Journal. vol. 9, no. 4, abstr. No. 5711; Glahn et al. 1996. J. Nutr. vol. 126, pp. 332-339; Glahn et al. 1998. J. Nutr. vol. 128, pp. 257-264, all herein incorporated by reference). These applications all required the extrinsic radiolabeling of the food Fe. Intrinsic radiolabeling as a means of tracking Fe absorption for plant foods has also been utilized, however, it is a relatively expensive and time-consuming process which requires a facility and technical staff to support the growth of radiolabeled plant materials. In addition, it may be difficult to incorporate sufficient radioactivity into the food studied, particularly for use in in vitro systems.
Thus, an in vitro model system that does not require radiolabeling of food Fe would be advantageous with respect to both time, cost, reliability and convenience. It would enable the measurement of food Fe availability in foods obtained directly from the producer or the supermarket shelf and would eliminate concerns of adequate radiolabeling of food Fe present in a complete meal.